1900] ACHROMATIC SPINDLE OF OSMUNDA 377 
1. OSTERHOUT, W. J. V.: Ueber Entstehung der karyokinetischen Spindle 
bei Equisetum. Jahrb. f. wiss. Bot. 30: 159-168. 1897. 
12, SHAW, W. R.: The fertilization of Onoclea. Ann. Bot. 12:161-285. 1898. 
13. -: Ueber die Blepharoplasten bei Onoclea und Marsilia. Ber. d. 
Deutsch. Bot. Gesells. 16:177-184. 1898. 
14. STEVENS, W. C.: Ueber Chromosomentheilung bei der Sporenbildung der 
Farne. Ber. d. Deutsch. Bot. Gesells. 16: 261-265. 1898. 
15, STRASBURGER, E.: The periodic reduction of the number of chromo- 
somes in the life history of living organisms. Ann. Bot. 8: 281-316. 
1894. See also Biol. Centralbl. 14: ——. 1894. 
———: Ueber Reduktionstheilung, Spindelbildung, Centrosomen, und 
Cilienbildung im Pflanzenreich. Jena. 1900. 
EXPLANATION OF PLATE XXII. 
The figures were outlined by the aid of an Abbé camera under the mag- 
hification given by a Zeiss apochromatic oil immersion lens 2™™ aper. 1.30, 
in combination with a Zeiss compensation ocular no. 8. In all cases the 
preparations were studied with the higher oculars, 12 and 18. 
Fic. 1, Mother cell with resting nucleus. 
Fic. 2. Mother cell with nucleus in spirem stage, and the kinoplasm dis- 
Unctly granular and fibrillar. 
IG. 3. The same, somewhat more advanced, showing the bipolarity of 
the kinoplasmic mass. 
1G. 4, A section which cuts off only a portion of the nucleus. 
Fic. 5. Chromosome stage. 
FIG. 6. Portion of a cell, showing part of the equatorial r 
spindle, 
egion of the 
Fig. 7. Later chromosome stage. 
Fig. 8. Chromosomes in equatorial plate after the disappearance of the 
nuclear membrane. 
Fig. 9. Anaphase, showing continuity of the primary fibers from pole to 
pole, and secondary fibers extending out from the poles. 
FIG. 10. A tripolar spindle. 
Fig. 
imary spindles on the left side; 
1G. 22. Late anaphase: one of the pr 
: : d out of the secondary fibers. 
the two 
“two other spindles shown have been forme 
1GS. 23-25. Successive telophases. 
